The use of peer mentoring in a successful high school jazz band was explored during one academic year of instruction using ethnographic techniques. Participants included primary informants (student jazz band members, director, assistant director, adult mentors) and secondary informants (guidance counselor, principal, parents, non-jazz band member students). Data analysis revealed that peer mentoring contributed to the success of a high school jazz band. Five themes emerged: (a) mentoring from the adult perspective, (b) peer mentoring for musicianship, (c) mentoring in rehearsals, (d) mentoring outside jazz band rehearsals, and (e) social mentoring. Suggestions for teacher educators include supporting, developing, and implementing peer mentoring, which can aid directors in instruction and rehearsal efficiency.